In discussing federalism, we often concentrate on the line where federal powers end and state powers begin. But the federal government and state...

In discussing federalism, we often concentrate on the line where federal powers end and state powers begin. But the federal government and state governments have concurrent powers as well. For example, both the federal government and state governments have powers of law enforcement, taxation, and general welfare. How do these concurrent powers affect citizens? Is it redundant for states to have some of the same powers as the federal government, or does the American public benefit?